Commit 6f8d4455 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: avoid fi->i_gc_rwsem[WRITE] lock in f2fs_gc 



The f2fs_gc() called by f2fs_balance_fs() requires to be called outside of
fi->i_gc_rwsem[WRITE], since f2fs_gc() can try to grab it in a loop.

If it hits the miximum retrials in GC, let's give a chance to release
gc_mutex for a short time in order not to go into live lock in the worst
case.

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 853137ce

fs/f2fs/data.c

+2 −2
Original line number Diff line number Diff line
@@ -2217,14 +2217,14 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to) 
	loff_t i_size = i_size_read(inode);



	if (to > i_size) {

		down_write(&F2FS_I(inode)->i_mmap_sem);

		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		down_write(&F2FS_I(inode)->i_mmap_sem);



		truncate_pagecache(inode, i_size);

		f2fs_truncate_blocks(inode, i_size, true);



		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		up_write(&F2FS_I(inode)->i_mmap_sem);

		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	}

}

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -1243,6 +1243,7 @@ struct f2fs_sb_info { 
	unsigned int gc_mode;			/* current GC state */

	/* for skip statistic */

	unsigned long long skipped_atomic_files[2];	/* FG_GC and BG_GC */

	unsigned long long skipped_gc_rwsem;		/* FG_GC only */



	/* threshold for gc trials on pinned files */

	u64 gc_pin_file_threshold;

fs/f2fs/file.c

+62 −57
Original line number Diff line number Diff line
@@ -797,8 +797,8 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr) 
	if (attr->ia_valid & ATTR_SIZE) {

		bool to_smaller = (attr->ia_size <= i_size_read(inode));



		down_write(&F2FS_I(inode)->i_mmap_sem);

		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		down_write(&F2FS_I(inode)->i_mmap_sem);



		truncate_setsize(inode, attr->ia_size);
@@ -808,8 +808,8 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr) 
		 * do not trim all blocks after i_size if target size is

		 * larger than i_size.

		 */

		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		up_write(&F2FS_I(inode)->i_mmap_sem);

		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



		if (err)

			return err;
@@ -962,8 +962,8 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len) 
			blk_start = (loff_t)pg_start << PAGE_SHIFT;

			blk_end = (loff_t)pg_end << PAGE_SHIFT;



			down_write(&F2FS_I(inode)->i_mmap_sem);

			down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

			down_write(&F2FS_I(inode)->i_mmap_sem);



			truncate_inode_pages_range(mapping, blk_start,

					blk_end - 1);
@@ -972,8 +972,8 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len) 
			ret = f2fs_truncate_hole(inode, pg_start, pg_end);

			f2fs_unlock_op(sbi);



			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

			up_write(&F2FS_I(inode)->i_mmap_sem);

			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		}

	}
@@ -1188,25 +1188,33 @@ roll_back: 
	return ret;

}



static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)

static int f2fs_do_collapse(struct inode *inode, loff_t offset, loff_t len)

{

	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

	pgoff_t nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;

	pgoff_t start = offset >> PAGE_SHIFT;

	pgoff_t end = (offset + len) >> PAGE_SHIFT;

	int ret;



	f2fs_balance_fs(sbi, true);

	f2fs_lock_op(sbi);



	f2fs_drop_extent_tree(inode);

	/* avoid gc operation during block exchange */

	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	down_write(&F2FS_I(inode)->i_mmap_sem);



	f2fs_lock_op(sbi);

	f2fs_drop_extent_tree(inode);

	truncate_pagecache(inode, offset);

	ret = __exchange_data_block(inode, inode, end, start, nrpages - end, true);

	f2fs_unlock_op(sbi);



	up_write(&F2FS_I(inode)->i_mmap_sem);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	return ret;

}



static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)

{

	pgoff_t pg_start, pg_end;

	loff_t new_size;

	int ret;
@@ -1221,25 +1229,17 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len) 
	if (ret)

		return ret;



	pg_start = offset >> PAGE_SHIFT;

	pg_end = (offset + len) >> PAGE_SHIFT;



	/* avoid gc operation during block exchange */

	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	down_write(&F2FS_I(inode)->i_mmap_sem);

	/* write out all dirty pages from offset */

	ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);

	if (ret)

		goto out_unlock;



	truncate_pagecache(inode, offset);

		return ret;



	ret = f2fs_do_collapse(inode, pg_start, pg_end);

	ret = f2fs_do_collapse(inode, offset, len);

	if (ret)

		goto out_unlock;

		return ret;



	/* write out all moved pages, if possible */

	down_write(&F2FS_I(inode)->i_mmap_sem);

	filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);

	truncate_pagecache(inode, offset);
@@ -1247,11 +1247,9 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len) 
	truncate_pagecache(inode, new_size);



	ret = f2fs_truncate_blocks(inode, new_size, true);

	up_write(&F2FS_I(inode)->i_mmap_sem);

	if (!ret)

		f2fs_i_size_write(inode, new_size);

out_unlock:

	up_write(&F2FS_I(inode)->i_mmap_sem);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	return ret;

}
@@ -1317,10 +1315,9 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
	if (ret)

		return ret;



	down_write(&F2FS_I(inode)->i_mmap_sem);

	ret = filemap_write_and_wait_range(mapping, offset, offset + len - 1);

	if (ret)

		goto out_sem;

		return ret;



	pg_start = ((unsigned long long) offset) >> PAGE_SHIFT;

	pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT;
@@ -1332,7 +1329,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
		ret = fill_zero(inode, pg_start, off_start,

						off_end - off_start);

		if (ret)

			goto out_sem;

			return ret;



		new_size = max_t(loff_t, new_size, offset + len);

	} else {
@@ -1340,7 +1337,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
			ret = fill_zero(inode, pg_start++, off_start,

						PAGE_SIZE - off_start);

			if (ret)

				goto out_sem;

				return ret;



			new_size = max_t(loff_t, new_size,

					(loff_t)pg_start << PAGE_SHIFT);
@@ -1352,6 +1349,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
			pgoff_t end;



			down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

			down_write(&F2FS_I(inode)->i_mmap_sem);



			truncate_pagecache_range(inode,

				(loff_t)index << PAGE_SHIFT,
@@ -1363,6 +1361,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
			ret = f2fs_get_dnode_of_data(&dn, index, ALLOC_NODE);

			if (ret) {

				f2fs_unlock_op(sbi);

				up_write(&F2FS_I(inode)->i_mmap_sem);

				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

				goto out;

			}
@@ -1374,6 +1373,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, 
			f2fs_put_dnode(&dn);



			f2fs_unlock_op(sbi);

			up_write(&F2FS_I(inode)->i_mmap_sem);

			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



			f2fs_balance_fs(sbi, dn.node_changed);
@@ -1402,9 +1402,6 @@ out: 
		else

			f2fs_i_size_write(inode, new_size);

	}

out_sem:

	up_write(&F2FS_I(inode)->i_mmap_sem);



	return ret;

}
@@ -1433,26 +1430,27 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len) 


	f2fs_balance_fs(sbi, true);



	/* avoid gc operation during block exchange */

	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	down_write(&F2FS_I(inode)->i_mmap_sem);

	ret = f2fs_truncate_blocks(inode, i_size_read(inode), true);

	up_write(&F2FS_I(inode)->i_mmap_sem);

	if (ret)

		goto out;

		return ret;



	/* write out all dirty pages from offset */

	ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);

	if (ret)

		goto out;



	truncate_pagecache(inode, offset);

		return ret;



	pg_start = offset >> PAGE_SHIFT;

	pg_end = (offset + len) >> PAGE_SHIFT;

	delta = pg_end - pg_start;

	idx = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;



	/* avoid gc operation during block exchange */

	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	down_write(&F2FS_I(inode)->i_mmap_sem);

	truncate_pagecache(inode, offset);



	while (!ret && idx > pg_start) {

		nr = idx - pg_start;

		if (nr > delta)
@@ -1466,16 +1464,17 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len) 
					idx + delta, nr, false);

		f2fs_unlock_op(sbi);

	}

	up_write(&F2FS_I(inode)->i_mmap_sem);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	/* write out all moved pages, if possible */

	down_write(&F2FS_I(inode)->i_mmap_sem);

	filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);

	truncate_pagecache(inode, offset);

	up_write(&F2FS_I(inode)->i_mmap_sem);



	if (!ret)

		f2fs_i_size_write(inode, new_size);

out:

	up_write(&F2FS_I(inode)->i_mmap_sem);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	return ret;

}
@@ -1722,8 +1721,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 


	inode_lock(inode);



	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	if (f2fs_is_atomic_file(inode)) {

		if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))

			ret = -EINVAL;
@@ -1734,6 +1731,8 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 
	if (ret)

		goto out;



	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	if (!get_dirty_pages(inode))

		goto skip_flush;
@@ -1741,18 +1740,20 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 
		"Unexpected flush for atomic writes: ino=%lu, npages=%u",

					inode->i_ino, get_dirty_pages(inode));

	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);

	if (ret)

	if (ret) {

		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		goto out;

	}

skip_flush:

	set_inode_flag(inode, FI_ATOMIC_FILE);

	clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);

	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);

	F2FS_I(inode)->inmem_task = current;

	stat_inc_atomic_write(inode);

	stat_update_max_atomic_write(inode);

out:

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	inode_unlock(inode);

	mnt_drop_write_file(filp);

	return ret;
@@ -1770,9 +1771,9 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) 
	if (ret)

		return ret;



	inode_lock(inode);

	f2fs_balance_fs(F2FS_I_SB(inode), true);



	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	inode_lock(inode);



	if (f2fs_is_volatile_file(inode)) {

		ret = -EINVAL;
@@ -1798,7 +1799,6 @@ err_out: 
		clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);

		ret = -EINVAL;

	}

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

	inode_unlock(inode);

	mnt_drop_write_file(filp);

	return ret;
@@ -2394,15 +2394,10 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in, 
	}



	inode_lock(src);

	down_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);

	if (src != dst) {

		ret = -EBUSY;

		if (!inode_trylock(dst))

			goto out;

		if (!down_write_trylock(&F2FS_I(dst)->i_gc_rwsem[WRITE])) {

			inode_unlock(dst);

			goto out;

		}

	}



	ret = -EINVAL;
@@ -2447,6 +2442,14 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in, 
		goto out_unlock;



	f2fs_balance_fs(sbi, true);



	down_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);

	if (src != dst) {

		ret = -EBUSY;

		if (!down_write_trylock(&F2FS_I(dst)->i_gc_rwsem[WRITE]))

			goto out_src;

	}



	f2fs_lock_op(sbi);

	ret = __exchange_data_block(src, dst, pos_in >> F2FS_BLKSIZE_BITS,

				pos_out >> F2FS_BLKSIZE_BITS,
@@ -2459,13 +2462,15 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in, 
			f2fs_i_size_write(dst, dst_osize);

	}

	f2fs_unlock_op(sbi);

out_unlock:

	if (src != dst) {



	if (src != dst)

		up_write(&F2FS_I(dst)->i_gc_rwsem[WRITE]);

out_src:

	up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);

out_unlock:

	if (src != dst)

		inode_unlock(dst);

	}

out:

	up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);

	inode_unlock(src);

	return ret;

}

fs/f2fs/gc.c

+20 −6
Original line number Diff line number Diff line
@@ -882,6 +882,7 @@ next_step: 
			if (!down_write_trylock(

				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {

				iput(inode);

				sbi->skipped_gc_rwsem++;

				continue;

			}
@@ -911,6 +912,7 @@ next_step: 
					continue;

				if (!down_write_trylock(

						&fi->i_gc_rwsem[WRITE])) {

					sbi->skipped_gc_rwsem++;

					up_write(&fi->i_gc_rwsem[READ]);

					continue;

				}
@@ -1048,6 +1050,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, 
		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),

	};

	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];

	unsigned long long first_skipped;

	unsigned int skipped_round = 0, round = 0;



	trace_f2fs_gc_begin(sbi->sb, sync, background,
@@ -1060,6 +1063,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, 
				prefree_segments(sbi));



	cpc.reason = __get_cp_reason(sbi);

	sbi->skipped_gc_rwsem = 0;

	first_skipped = last_skipped;

gc_more:

	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {

		ret = -EINVAL;
@@ -1101,7 +1106,8 @@ gc_more: 
	total_freed += seg_freed;



	if (gc_type == FG_GC) {

		if (sbi->skipped_atomic_files[FG_GC] > last_skipped)

		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||

						sbi->skipped_gc_rwsem)

			skipped_round++;

		last_skipped = sbi->skipped_atomic_files[FG_GC];

		round++;
@@ -1110,15 +1116,23 @@ gc_more: 
	if (gc_type == FG_GC)

		sbi->cur_victim_sec = NULL_SEGNO;



	if (!sync) {

	if (sync)

		goto stop;



	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {

			if (skipped_round > MAX_SKIP_ATOMIC_COUNT &&

				skipped_round * 2 >= round)

				f2fs_drop_inmem_pages_all(sbi, true);

		if (skipped_round <= MAX_SKIP_GC_COUNT ||

					skipped_round * 2 < round) {

			segno = NULL_SEGNO;

			goto gc_more;

		}



		if (first_skipped < last_skipped &&

				(last_skipped - first_skipped) >

						sbi->skipped_gc_rwsem) {

			f2fs_drop_inmem_pages_all(sbi, true);

			segno = NULL_SEGNO;

			goto gc_more;

		}

		if (gc_type == FG_GC)

			ret = f2fs_write_checkpoint(sbi, &cpc);

	}

fs/f2fs/segment.c

+5 −1
Original line number Diff line number Diff line
@@ -445,8 +445,10 @@ int f2fs_commit_inmem_pages(struct inode *inode) 
	int err;



	f2fs_balance_fs(sbi, true);

	f2fs_lock_op(sbi);



	down_write(&fi->i_gc_rwsem[WRITE]);



	f2fs_lock_op(sbi);

	set_inode_flag(inode, FI_ATOMIC_COMMIT);



	mutex_lock(&fi->inmem_lock);
@@ -461,6 +463,8 @@ int f2fs_commit_inmem_pages(struct inode *inode) 
	clear_inode_flag(inode, FI_ATOMIC_COMMIT);



	f2fs_unlock_op(sbi);

	up_write(&fi->i_gc_rwsem[WRITE]);



	return err;

}

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